The present application relates to systems and methods for forming ultra-conductive wire. It finds particular application in conjunction with nano-engineered ultra-conductive copper wire, and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Since the discovery of electricity, pure metals were thought to have the lowest resistance to transporting electrical current at room temperature. This assumption defined the upper limits of the efficiency and consequently the size and power consumption of all conventional electric machines and devices. Recently, the discovery of carbon nanotubes (CNTs) introduced a new class of metallic carbon nanotube-based conductors (known as ballistic conductors) that are orders of magnitude better at carrying current than pure metals. Unfortunately, conventional approaches to harnessing this potential have not been successful thus far because the nanotubes produced to date are on the order of a few millimeters in length and no one has been able to make practical length segments and/or continuous bundles of wires with these properties. Other attempts at forming nano-composite metal/nanotubes matrices by starting from powdered metals and/or by molecular level mixing failed to produce gains in the electrical conductivity.
Conventional methods are further lacking for several reasons. For instance, it has not been possible to date to effectively disperse nanotubes by traditional mixing methods because of the high Van der Waals forces between the nanotubes. Moreover, the use of traditional surfactants and/or alloying agents to assist in dispersing the nanotubes introduces impurities and reduces the electrical conductivity. Sub-melt processes, such as sintering, create residual porosity and this, along with the previously mentioned items, results in undesirably large contact resistances and the formation of Schottky barriers. Furthermore, non-alloying two-phase materials, such as molten copper and nanotubes, do not mix because of the considerable mismatch between their densities and because copper does not wet carbon. Still furthermore, static processes like sintering are not suitable since they cannot disperse or orient the nanotubes in a manner that increases conductivity.
The systems and methods described herein facilitate forming nano-composite ultra-conductive wire while overcoming the above-mentioned deficiencies and others, as will be appreciated by those of skill in the art.